Apparatus for the production of esters



A. A. BACKHAUS.

APPARATUS FOR THE PRODUCTION OF ESTERS.

APPLICATION FILED AUGJ, 191s.

1 %UQ85L ented Dec. 2U, 1921.

i5 19 33 3e E I I a 15 1? 51 I V 14 18 i 22 12 33 M20 OFF 1 C ARTHUR A. BAGKHAUS, 0F BALTIMORE, MARYLAND, ASSIGNOR TO U. S. INDUSTRIAL ALCOHOL 00., A CORPORATION OF WEST VIRGINIA.

anai.

Specification of Letters Patent.

Patented Dec. 20, 121.

Application filed August 7, 1918. Serial No. 248,756.

To all whom it may concern:

Be it known that I, ARTHUR A. BACK- HAUs, of Baltimore, in the State of Mary land, have invented a certain new and. useful Improvement in Apparatus for the Production of Esters, and do hereby declare that the following is a full, clear, and exact description thereof.

My invention relates to an ap aratus by means of which esters may be made continuously, that is to say, without interruption, and has reference to the manufacture of many different kinds of esters in this way.

The object of my invention is to provide an apparatus by means of which esters may be manufactured continuously, instead of requiring the repeated interruption of the operation that was hitherto found necessary. A further object is to provide an apparatus of this character by means of which esters, substantially entirely free from water, may be obtained. Further objects of my invention will appear from the detailed description contained hereinafter.

The object of my invention is especially to provide an apparatus adapted to operate upon strong organic acids, and which is so arranged that the ester is largely formed outside of the distilling apparatus. in order to relieve the latter of the function of forming the ester as far as possible, so as to increase the capacity of the still in the distillin operation.

'le my invention is capable of being carried out in many different ways, for the purpose of illustration I have shown only one type of apparatus made in accordance with my invention in the accompanying drawings, in which- Figure 1 is a diagrammatic representation of an apparatus made in accordance with my invention, and

Fig. 2 is an enlarged vertical section of a I detail of one of the columns therein.

I shall describe my invention as it is applied to the treatment of a strong acid, as for example, glacial acetic acid with methyl alcohol in the production of methyl acetate, although it is to be understood that my apparatus is applicable to the production of many different esters and from materials of many different strengths.

In the drawings, I have shown a column still 1 comprised of an outer casing 2, and a large number of plates or pans 3 having central openings 4 covered by hoods or bells 5, the edges of which are sealed in the liquid earned by said plates 3, the adjacent plates being connected by overflow pipes 6. I supply to the upper part of the side of the column still 1 continuously by means of a trapped pipe 7, a mixture of sulfuric acid. glaclal acetic acid and methyl alcohol from a mixing tank 8 provided with a propeller 9, carried upon a shaft 10 and rotated by a pulley 11 from any suitable source of power. Sulfuric acid is continuously fed to the tank 8 by means of a pipe 12 having a needle valve 13 and a sight feed 14 connected to a sulfuric acid tank 15. In this instance. the sulfuric acid is fed to the mixing tank 8 in the proportion of two parts by weight of sulfuric acid having a strength of 50 to 66 Rd, to ten parts by weight of glacial acetic acid which is fed continuously to the tank by means of a pipe 16 having a needle valve 17 and a sight feed 18 connected to an acetic acid tank 19. At the same time methyl alcohol having a strength of 95 to 98% is continuously fed to the tank 8 in the proportion of six parts by weight, by means of a pipe 20 having a needle valve 21 and a sight feed 22 connected to an alcohol tank 23. Initially. before feeding through the pipe 7, a quantity of methyl alcohol suflicient to fill the pans in the still 1, is introduced by means of a valved pipe 24. The reaction by which methyl acetate is formed takes place partly within the tank 8. although the reaction takes place also in part in the column 1. The still is heated at its lower end by means of a tubular heater 25 having inlet and outlet steam pipes 26 and 27 The efliuent water and sulfuric acid are conducted away from the still 1 by a pipe 28 having a trap 29 therein. From the upper portion of the still 1, a vapor discharge pipe 30 is provided to conduct away the vapors of the methyl acetate and alcohol, which vapors may have a proportionate composition of 50 parts by weight of methyl acetate and 50 parts by Weight of methyl alcohol to a dephlegmator 31 having a trapped return pipe 32 for returning the condensed alcohol to the top of the column still 1, as well as a discharge pipe 33 for conveying the methyl acetate vapors to a second column 3 1 constructed in the same manner as the column 1, except that this column has a trapped discharge pipe 35 to convey away the methyl alcohol from the lower portion of said column 34 to the column 1, at a point which maybe opposite to. the entry of the pipe 24. The vapors from the pipe 33 ascend in the column 34: through a descending current of methyl alcohol, and the vapors of methyl acetate containing a small amount of metlgyl alcohol, are conveyed by a pipe 36 to a ephlegmator 37, from which the condensed methyl alcohol returns by a trapped pipe 38 to the top of the column 34, while the vapors of methyl acetate are conducted by a pipe 39 to a condenser 40, from which thejcon densed methyl acetate is drawn ofiibya The methyl acetate. produced in j pipe 41. this manner is substantially water-,free-as shown by test with anhydrous copper sull fate.

alcohol are ordinarily fed into the mining tank 8 continually, in which tank the methyl 1 acetate is partly formed, and the mixed' liquids are drawn off by the pipe 7 and "sup plied to the column still 1. In the column still 1, the formation of methyl acetate, is

completed, while the heat which'is appli'e'dto said column drives off the vapors- 0f as well as some vapors of" methyl acetate, methyl alcohol which pass into the dephlegmator 31 from which the condensed water carrying some alcohol is returned to the top of the column 1 to form liquid seals, and to provide a descending body of methyl alcohol therein. The methyl acetate vapors thus partly freed from methyl alcohol pass then to a second or rectifying column 34 in which nearly all of the methyl alcohol is removed and returned as a liquid to the column 1, while the methyl acetate vapors containing a small amount of methyl alcohol pass out of the same into the dephlegmator 37 from which point the remaining quantity of methyl alcohol is returned to the column 34;.

, The methyl acetate vapors then pass to the condenser 40 from which the condensed methyl acetate may be continually drawn off.

In carrying out the process the esterification is carried out more completely and more rapidly by reason of the continual removal of the acetate from the place where the reaction takes place and because of the provision of much larger quantities of methyl alcohol than are needed for the reaction. he quantity of methyl alcohol present is four or five times the quantity of methyl alcohol required in the reaction. Furthermore, the smaller the percentage of the acetic acid in the descending current of liquid in the still 1, which becomes weaker in the acid as it descends, the larger the quantity of methyl alcohol required to offset the difficulty of- In the operation of my invention, -thesulj furic acid, glacial acetic acid and-fmethyl the liquid is very weak in acetic acidand in such quantity as to complete the esterification before the liquid reaches the lower end of the column still 1. 'Because of the strength of the acetic acid the reaction can be. effected to a large degree merely by mixing the reagents, and this is done, therefore, in the tank 8, so as to relieve the still 2 correspondin ly, in order to increase its capacity@ t will be understood that other acids and 7 other alcohols ma be used insteadlof the methyl alcohol an acetic acid, such'fo'r ex-} ample, as formic acid and" ethyl alcohol. Also crude pyroligneous acid may be used, as it contains acetic "acidand' methyl alcohol, etc".i Also,- instead of sulfuric acid-anothercataly's't may be used, as niter cake, or hydro chlorifc m any phosphoric. acid. v Organic ".acids,=.such,as acetic acid, may also beu'sed asicatal ytic in the 1 promotion of those reac-- actually enter as reacting ingredients;.'f-

.i1'i -:detail,-- I wish it m be understood that many "changesmay be'made therein; without deg ee v from the' spirit thereof; 3

I n p on of acolumn still, an inlet ipe the top, thereof, an ",outlet I near'its-botto second column still, a'de- Y livery pipeleading cfrom the topof the first still to the second still, a return pipe leading from the bottom of the second still to the bottom of the first still,sand avapor exitjatthe top of the second St ll. Y

2. The combination of a column still, an

inlet pipe near the top thereof and an outlet near its bottom, a second column still, a delivery pipe leading from the top of the first still to near the middle-of the second still, a

return pipe leading from the bottom of the second still to a point near the bottom of the first still, and a vapor exit near the top of the second still.

3. The combination of a column still, an inlet pipe near its top and an outlet near its bottom, a second column still, a delivery pipe leading from the top-of the first still to the second sti1l,a condenser inthe circuit of said pipe, a return pipe leading from the bottom of the second still to a point near the bottom of the first still, a vapor exit leading from the oint near the top of the second still to a con enser, and a vapor exit from the condenser.

4. The combination of a column still, an inlet pipe near the top thereof connected with a mixing tank containin an agitating means, an outlet pipe near the ottom of the still, a second column still, a delivery pipe leadin from the top of the first still to the second still a return pipe leading from the bottom of the second still to a point near the bottom of the first still, and a vapor exit at the top of the second still.

85- r ,tions,as' described, into whichthey do not 5. The combination of a column still, an pipe leading from the bottom of the second inlet pipe near the top thereof connected with still to near the bottom of the first still, and a mixing tank containing agitating means, a vapor exit and condenser at the top of the separate supply tanks feeding to said mixing second still. 5 tank, a pipe connected with one of said sup- In testimony that I claim the foregoing 15 ply tanks and leading to a point near the bot- I have hereunto set m hand.

tom of the still, an outlet near the bottom of ARTHU A. BACKHAUS. the still, a second column still, a delivery Witnesses: pipe leading from the top of the first still to A E. J. WINTER,

1. near the middle of the second still, a return J. B. JOHNSON. 

